Pharmacological inhibition of histone deacetylase 6 and DNA damage repair enhances radiosensitivity in melanoma.

Melanoma, a malignant tumour originating from melanin-producing melanocytes, poses a significant threat to human health, including cutaneous melanoma and uveal melanoma (UM). Although surgical resection remains a primary treatment modality, radiotherapy has emerged as another therapeutic option, particularly for UM. Nevertheless, the adverse effects induced by radiotherapy are considerably pronounced. In this study, we identified WT-161, a selective histone deacetylase 6 (HDAC6) inhibitor, as a potent radiosensitizer for melanoma therapy through high-throughput drug screening. Mechanistically, inhibition of HDAC6 disrupted its interaction with DNA damage repair proteins (DDB2 and DEK) and suppressed gene expression in the DNA damage repair pathway, leading to the accumulation of irradiation-induced DNA damage and tumour regression. Our findings establish HDAC6 as a predictive biomarker for radiation response in melanoma and demonstrate that pharmacological inhibition of HDAC6 with WT-161 could expand the clinical utility of radiotherapy in patients with UM.